<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>
  <ol id="box">
    <li>q</li>
    <li>w</li>
    <li>e</li>
  </ol>
  <script>
    // var list = document.getElementsByTagName('li')
    // for(var i = 0; i < list.length; i++) {
    //   console.log(list[i])
    // }

    
    var box = document.getElementById('box')
    var list = box.getElementsByTagName('li')
    console.log(list)
  </script>
</body>
</html>